Heater blower problem

[Beedee]

Need a little help here please.
I've been working out of town for the past several weeks, only have a couple of days off, then have to go back. My heater fan works when it wants, has done it twice now. I haven't got much time to spend trying to find the problem. Has anybody else had the same problem and found a fix. I did a search, but couldn't seem to find the answer that I was looking for. Help......

[diesel65]

Are you having problems with all speeds or just one speed?

The 99 suburbans in my fleet burned the electrical connector that is behind the glove box.
The connector is the main power feed for the heater and a/c circuit, pull the glove box out and look for a heavy guage red wire located to the left of the PCM. There should be a black male-female connector inline and you might find it burnt after you unplug it.
If it is burnt I usually just cut it out and use a butt connector but I have seen the butt connector starting to burn also, so the best thing would be to solder the wires together.

I have also seen the blower switch connector also burn up, so you would need to pull the dash and then pull the control head to be able to unplug the connector and inspect.
If you find that connector is burnt, there is a repair connector available from GM. If you need the part number let me know and I will try to dig it up.

[markrinker]

Why are the connectors melting? Does the motor draw progressively more and more as it ages?

Maybe its wise to change the motors, too...

[Beedee]

When it quits, it is all speeds.
The first time it happened, I had shut the truck off long enough to get a coffee, came back and no heater, scractched head, drank coffee, headed for home and about a kilometer from home it started back up, no bump in the road to jar wires or any thing like that. The second time, it cut out and back in as I was driving, only off for a min or two. I can go check the wires later tonight. Thanks for the help, and I'll let you know what I found.
Brian

[damork]

I had this happen with mine 5 years ago. I pulled out the connector, cut the wires and soldered a heavy connector in place of it. I made sure it was at least 12 gauge wires and I haven't had problems since.

The OEM connector had poor crimps where the plugs connected to the wire. High current through small or weak connections cause heat.

[Beedee]

Finally had time to check things out. Found the big red wire behind the glovebox. Connection was good, just to make sure that it was the right one, I unplugged it. This wire is only for the highest speed on the blower, there is also a relay located more towards the driver, ontop of the heater, it only clicks when the heater control is moved to the high speed. I don't have time to remove the dash, so am going to say a prayer to the heater gods and take my chances. Only have a 4 day shift this time. Hopefully it won't give up while I'm in transist :eek:
Brian

[rjwest]

Had same problem foe a year, mostly in summer...
Carried big stick to jump start it.....

Changed relay, fixed contacts, etc.
No fix
Had to replace the Blower motor.....Napa has part

Not a bad job, Just lift up and bend back the insulation and cut around the top to get insulation all way up.
7 mm wrench ( ?? ) for motor...

[Keith Richards]

I've been having a problem for a while.Only the 3rd and 4th speed work.The connection behind the fan switch is melted.You can pull your dash cover pretty easily to check it and replace if necesarry.

[Beedee]

Back in town, Got called back to my regular job starting tomorow. Heater hasn't missed a beat since I wrote the first post. Everything that I have had time to check has been Okay. Since I'm back in town again, I'll just let it develope for a few days. Thanks for all the tips.
Brian

[rjwest]

Get the 3 foot club ( persueder ) light to moderate tap.

[Beedee]

I have a 20 lb sledge hammer in the back of the garage just in case the club doesn't work :D :D :D
Brian

[rjwest]

No No NO, That's to destroy the entire truck,
when total frustration sets in....


There have been times when, Just glad the 20lb er was't handy...

[GMC Hauler]

Check your ground on the rear passenger side of the intake manifold. I recently had a no start problem, and one of the other symptoms was that the heater blower motor didnt work. It turns out is was a loose ground.
I have also had this ground act up intermittently. Some of the other things that flow through this ground is the starter relay and the glow plug relay. But if you are running, you wouldnt see these other symptoms.
I have also deduced that the bolt that my wire was connected to (second from the back passenger side on the intake manifold) isnt the best bolt for the job. I state this because I use sealant on this bolt, because it can leak (open to the crankcase) if sealant isnt applied. I believe that this bolt can sometimes not make a good ground because of the sealant (i saw 4 ohms resistance from the bolt to the intake manifold). I moved those grounds to one of the 4 threaded towers that was left when I removed the diesel intake cover. So far, no more problems....

[ 01-16-2005, 01:11 PM: Message edited by: GMC Hauler ]